Door locking device

ABSTRACT

A striker of ring shape fixed to a doorway engages and rotates a disk latch rotatably supported on a corresponding door into a striker locking position when the door is closed, and the latch is thus held by a semicylindrical end of a detent having a cylindrical body, the semicylindrical end and cylindrical body being snugly but rotatably supported against transverse force respectively by semicylindrical and cylindrical concavities formed in a part supported on the door. When the latch is in the striker locking position, the striker is in a position substantially intermediate between the axes of the latch and the detent.

' Kazaoka et al.

[54] DOOR LOCKING DEVICE [75] Inventors: Kenichi Kazaoka; Nozomu Torii,

both of Kariya, Japan [73] Assignee: Aisin Seiki Kabushiki Kaisha,

Kariya-shi, Japan [22] Filed: Feb. 4, 1970 [21] Appl. No.: 8,614

[30] Foreign Application Priority Data Feb. 8, 1969 Japan ..44/9474 Feb. 9, 1969 Japan ..44/12379 [52] U.S. Cl ..292/2l6, 292/DIG. 41 [51] Int. Cl ..E05c 3/24 [58] Field of Search ..292/2l6, 198, 210, 3, 4, 280

[56] References Cited UNITED STATES PATENTS 3,081,117 3/1963 McDaniel ..292/2l6 3,116,082 12/1963 Chanaryn et a1. ....292/216 X 180,293 7/1876 Wallis ..292/210 3,058,766 10/1962 Chanaryn et a1. ..292/2l6 X 51 Jan. 9, 1973 3,415,559 12/1968 Jeavons ..292/216 3,416,826 12/1968 Putsch et a1. ....292/198 3,432,198 3/1969 Connor ..292/216 FOREIGN PATENTS OR APPLICATIONS [57] ABSTRACT A striker of ring shape fixed to a doorway engages and rotates a disk latch rotatably supported on a corresponding door into a striker locking position when the door is closed, and the latch is thus held by a semicylindrical end of a detent having a cylindrical body, the semicylindrical end and cylindrical body being snugly but rotatably supported against transverse force respectively by semicylindrical and cylindrical concavities formed in a part supported on the door. When the latch is in the striker locking position, the striker is in a position substantially intermediate between the axes of the latch and the detent.

6 Claims, 7 Drawing Figures PATENTEDJAN 91973 3.709.537

sum 1 OF 3 INVENTOR S ATTORNEYS PAIENIEnJu 9 am SHEET 2 BF 3 INVENTORS 5 Kn an a K n 131 754...... M pM ATTORNEYS INVENTORS K. Kn znaKA A. 7 I,

133%, ruvwouz ATTORNEYS noon LOCKING DEVICE BACKGROUND OF THE INVENTION This invention relates to door locking devices and more to a new door locking device for doors of motor vehicles.

In recent years, automobile traffic accidents have increased, resulting in an unfortunate increase in death or fatal accidents. In many cases, deaths are due to accidental doors opening or caused by shock of collision of cars. In view of this situation, it is deemed very important as a safety measure to increase the breaking strength or resistance to accidental unlocking of door lock devices.

As is known, when an abnormally great breaking force is imparted to a vehicle door locking device of prior design, at the time of a collision, for example, mutual engaging parts of a striker and latch element, a pivoted part of the latch element, auxiliary engaging parts of the latch element and detent means for stopping the turning of the latch element, and a pivoted part of the detent means are especially apt to be damaged or broken.

SUMMARY OF THE INVENTION It is an object of the present invention to increase the mechanical strengths of these parts which are subject to damage, particularly the above mentioned auxiliary engasing parts of the latch element, stopping means, and pivoted part of the detent means, merely by rationally designing the configuration and organization of these parts, without any inordinate enlargement of parts or of the entire locking device assembly, with particular consideration being given to the feasibility and economy of fabrication of these parts with high precisIon.

Another object of the invention, in a general aspect thereof, is to provide a door locking device of the above stated character which is of simple construction and operation, capable of being manufactured and maintained at low cost, and easily operated by hand with a comfortable, pleasant tactile sensation.

In general, the present invention contemplates the provision of a door locking device for vehicles which has the following functional features.

1. Keeping the door in a closed state (when the door is closed, but is still unlocked).

2. Permitting the door (which is in the state mentioned in l) to be opened both from inside and outside of the car.

3. Locking from inside of the car for safety or protection against theft.

4. Locking by use ofa key from outside of the car for protection against theft.

5. Automatic release of locking when the door is closed after the locking operation has been carried out from inside of the car by mistake (to avoid locking when the key is left behind in the car) 6. Locking without use of the key (keyless locking, this is desired, for example, on rainy days) According to the present invention, briefly summarized, there is provided a door locking device characterized by the combination of a striker fixed to a doorway frame for receiving a door, a latch member rotatably supported on the door and adapted to engage with and be rotated into a striker locking position by the striker when the door is closed, a detent having a configuration which, in at least one part thereof, constitutes a part of a cylinder and rotatably supported on the door, the detent being rotatably operated by the latch member to catch and lock the latch member in the locking position and being operable to release the latch member, a concave cylindrical bearing surface formed in a part supported on the door for rotatably backing up the detent against transverse forces, and an unlocking mechanism for operating the detent to release the latch member, with the position of the striker in the locked position being substantially intermediate between the axis of rotation of the latch member and the axis of rotation of the detent.

Now, the present invention will be described in detail with respect to a preferable embodiment thereof and with reference to the accompanying drawings, in which like parts are designated by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a front view of a door locking device according to an embodiment of the present invention, in which a cover plate is removed to show a door lock and a striker, with these two being completely out of engagement;

FIG. 2 is a front view similar to as FIG. 1, but showing the state when the door lock and the striker are fully engaged;

FIG. 3 is a fragmentary sectional view along the line III-III in FIG. 2;

FIG. 4 is a view of the device shown in FIG. 1 from its rear side, and shows an embodiment of an operating mechanism in its unlocked position;

FIG. 5 is a view similar to FIG. 4, but showing the operating mechanism in locked position;

FIG. 6 is a fragmentary front view indicating the rela-' tionship between a main engaging part and an auxiliary engaging part in a door locking device of prior design; and,

FIG. 7 is a fragmentary vertical section, showing an undesirable state of engagement when the device shown in FIG. 6 is subjected to a load in the longitudinal direction of the vehicle.

DETAILED DESCRIPTION 7 In the drawings reference character A designates a door-lock according to the invention attached to a side panel C (FIG. 3), B designates a striker, which being secured to a door-post D (FIG. 3), keeps the door in a closed state when engaged with the door-lock A and includes a base plate B secured to the post D and a locking ring B, engageable with the lock A.

As shown in FIG. 3, the door-lock consists principally of a cover plate 7, a main body 1 and base plate 6 and is fixed to a side panel of said door as a unit by fixing means such as bolts. The body 1 is formed from synthetic resin, having depressions la, lb, 1c, 1d and Is, one of which 1d is elongated in a horizontal direction (from right to left as viewed in FIG. I) at a position spaced appropriately downwards from the turning axis of a latch 2 (to be described below), and opens to the left as viewed in FIG. 1), so that the locking ring B of the striker is permitted to enter into or move out of this depression.

Further (FIG. 3), in the cover plate 7 and in the side panel C, there are provided slots such as 7a of similar shapes as the depression 1d for the entrance and extraction of the striker into and out of the locking ring 3,. A pin (pivot) 2a (FIG. 1), forming the turning axis of the latch 2, is pivotably supported in the depression 1e at the middle part of the body 1, i.e., the latch 2 is pivoted in this depression 1e of the body 1 turnably about the pin 2a.

In the latch 2, outside of the pin 2a (FIG. 1), there is formed an open-ended slot 2b, which is shaped to engage with the ring B and to be turned by the latter into positions of safety engagement and full engagement, when the leading side of the locking ring B (of the striker), enters into the depression 1d through the slot 7a of the cover plate 7 and a slot C, of the side panel C when the door is closed and to be forced by the ring B to turn in the opposite direction when the door is opened. When the door is opened, this slot 2b has its opening aligned with the depression 1d of body 1 and its bottom against the center of the pin 2a, as shown in FIG. 1. Further, the latch 2 is provided with a pin 4, which is being urged to turn clockwise about the pin 2a by a coiled compression spring 5 located in the depression 1c of arcuate shape and arranged between the pin 4 and the bottom of this depression lc.

In the depression 1b of cylindrical shape formed in the periphery (outer boundary) of the depression 1a of the body 1, a locking detent 3 is snugly and rotatably received and has a crescent (semi-circular) cross section defined by a part of circular wall 3a concentric with the axis of rotation of the detent 3 and a vertical wall 3b. The circular or arcuate wall 30 is adapted to engage selectively with a first tooth 2c (for safety engagement) or a second tooth 2d (for full engagement) formed on the periphery of the latch 2, with these teeth 2c and 2d being defined by a convex surface opposite the surface of the circular wall 30, a concave surface having a radius of curvature greater than that of the wall 30, or a flat plane. The second tooth 2d is formed at the counterclockwise side (as seen in FIG. 1) of the open end of slot 2b, while the first tooth 2c is formed in the periphery of the latch 2 at a point forward counterclockwise from that of the tooth 2d.

Further, the periphery of the latch 2 at the counterclockwise side of the first tooth 20, through a certain distance starting from the latter, is formed into a inclined slope 2e, which is suitable for engaging the vertical wall 3b of the detent 3 so as to turn the same in the clockwise direction, and a peripheral part 2f between the tooth 2c and the tooth 2d is also inclined in the same way. An axially projecting pin 3c (FIG. 3) is pivotably supported by the base plate 6 of the doorlock, with the pin 30 at its free end being fixed to the middle part of an open plate 8. Accordingly, the locking detent 3 is pivotably supported by fitting with the base plate 6 and with the aforesaid cylindrical depression 1b, while the detent 3 and the open plate 8 are caused to move unitarily.

An example of an operating mechanism suitable force in this invention will now be described. FIG. 4 shows the unlocked state, i.e., the state in which the release button (not shown in the drawings) is pushed and the door is permitted to be opened by being pulled in the opening direction. A generally T-shaped openlever 12 is, at its middle part, pivotably secured to the base plate 6 by means of a pin 13. The lever 12 has a first arm 12a at its left side. The free end of the arm 12a has a connecting lever 15 pivoted thereto by means of a pin 14. The lever 12 also has a second arm 12b at its right side, which extends through a slot 6b formed in a vertical plane 6a bent into the front side (the nearer side as viewed in the drawing) of the base plate 6, with the purpose of this slot 6b being to limit the motion of the lever 12.

The lever 12, further, has an upward extending arm 120, which is related to the action of the release button when the latter is pushed in from outside to open the door. Between an anchor 12d and a hole 6e provided in the vertical plane 6a of base plate 6, there is placed a spring 23, which urges the lever 12 to turn clockwise about the pin 13. A locking plate 16 is pivotably secured at its middle part, the lower part (in the drawings) of by the pin 30, and at the upper side (viewers side of FIG. 4) of the plate 16, and T shaped open plate 8 is fixed to the pin 30. The locking plate 16 at its right end 160 (seen in FIG. 4) extends through a slot 60 formed in the vertical plane 60, with the slot 60 serving to limit the swinging motion of the plate 16 about the pin 3c.

In the locking plate 16 adjacent its righthand end 16a, there is provided a hole 16b, which is to be connected with an inside locking member, such as an inside push knob, (not shown in the drawings), which serves to keeps the door in the locked position, i.e., the position in which the door cannot be opened by pushing in the open button or by pulling the door in opening direction. At the lefthand end of the horizontal part of the plate 16 there is provided a hole 16c, which is to be connected to a member (not shown in the drawings) operated by the action of a key. The plate 16 has an arm 16d, which extends upwardly from between the hole 16c and the pin 30 and has a pin 20 fixed thereto. Moreover, in the plate 16 there is formed a hole 16e between the hole 16b and the pin 30, and, between the hole 16c and a hole 6h formed in the base plate 6, there is installed a turn-over spring 24.

The above-mentioned pin 20 fixed to the locking plate 16 is snugly received in a groove formed by a hook shaped part 150 of the connecting lever 15. A tension spring 19 is provided between a hole 8a formed in the open plate 8 and a spring anchor 6d formed in the base plate 6 and has the function of urging the plate 8 in the clockwise direction, while a stopper 6g provided on the base plate 6 is in engagement with the first (lower) arm 8b of the plate 8, for limiting the clockwise turning of the latter.

The second arm of the open plate 8, which extends from the plate to the left in FIG. 4, is bent toward the viewer's side (in FIG. 4) at its left end. Owing to such arrangement, when the open-lever 12 turns in the counterclockwise direction, and the connecting lever 15 is moved downward as viewed in the drawing, the second arm 8c is engaged with the lower end of the lever 15, causing the open plate 8 to turn in the counterclockwise direction about the pin 30. A top end 8d of the open plate 8 extends to a height at which the end 8d can engage the hook shaped part 15a of the connecting lever 15 and is bent at a right angle toward the viewers side of the drawing (see FIG. 3). As shown in FIG. 3, in

the right hand end of the vertical plane 6a of the base plate 6, there is pivoted an inside open lever 21 to the plane 6a by means of a pin 22, which lever 21 is engageable at its left end (engaging part) 21a with the second arm 12b of the open lever 12.

The device of the above described organization according to this invention operates as follows.

When the door is in its open state, the latch 2 and the detent 3 are positioned as shown in FIG. 1. When the door is closed, the striker B enters into the slot 2b along the depression 1d of the body 1, and by engaging the second tooth 2d of the latch 2, causes the latter to turn in the counterclockwise direction. At this time, the latch 2, contacting the vertical wall 3b of the detent 3, causes the latter to turn in the clockwise direction(seen in FIG. 1) against the force of the spring 19 until the first tooth 2c of the latch 2 is brought into engagement with the circular peripheral wall 3a of the detent 3 (safety engagement).

After the continued movement of the door toward the closed position, the second tooth 2d of the latch 2 is brought into engagement with circular wall 3a of the detent 3 (full engagement), and, the latch and the detent are held in this state.

In this closed state, which is shown in FIGS. 2 and 3, if the opening button (for opening the door) is operated in the opening direction, the release arm 12c of the open lever 12 is shifted to the left in FIG. 4, causing the lever 12 to turn in the counterclockwise direction. As a result, the connecting lever 15 is forced downwards in the drawing along the pin 20, whereby the second arm 8c of the open plate 8 is pushed downward, causing the plate 8 to turn about the pin 3c in the counterclockwise direction as seen in FIG. 4. By this turning, the locking detent 3 is also turned in the clockwise direction as seen in FIG. 1, resulting in releasing of engagement between the detent 3 and the first or second tooth 2c or 2d of the latch 2. Consequently, the latch 2 is allowed to turn in the clockwise direction as seen in FIG. 1 under the action of the spring 5, until the open end of slot 2b comes into alignment with the slot 7a of cover plate 7 and with the depression 1d of body 1. In this position (which is shown in FIG. 1), the striker B is released from engagement with the latch 2, and the door is allowed to be opened.

In the closed state of the door, if an inside open handle is operated to the opening direction, the inside open lever 21 is turned in the clockwise direction in FIG. 3 about the pin 22, causing the engaging part 21a of the lever 21 to lift the second arm 12b of open lever 12 upward (as seen in FIGS. 3 and '4) so as to turn the lever 12 in the counterclockwise direction about the pin 13. Thus, the same effect as described above (when the outside opening button is operated) is attained, and the door is allowed to be opened in the same way.

When the door is locked from outside by using a key, the locking plate 16 is turned in the clockwise direction about the pin 3c through a lever(not shown) connected to the hole 16c of locking plate 16. When it is desired to lock the door from inside, the locking plate 16 is caused to turn in the clockwise direction about the pin 3c by, for example, pushing down an inside locking push knob connected to the hole 16b of locking plate 16. In either case, the pin 20 fixed to locking plate 16 is simultaneously turned in the same direction about the pin 3c, forcing the lower end of connecting lever 15 to the right as seen in FIG. 4, until the lever 15 takes a position as shown in FIG. 5 by full lines. When the mechanism is in this state, the turn-over spring 24, which has been previously urging the locking plate 16 in the counterclockwise direction, begins to urge the same plate in the clockwise direction.

In the position shown in FIG. 5, if the opening button or the inside opening handle is operated and the open lever 12 is turned in the counterclockwise direction to a position shown by dotted lines in FIG. 5, the connecting lever 15 will be moved downward to a position as shown by other dotted lines. In this case however, the lower end of lever 15 cannot engage with the second arm 8c of open plate 8, and, consequently, the open plate 8 being left unmoved, and the door is not allowed to open, i.e., the door is kept in locked state.

When the door is closed, and the inside locking pushknob is kept in locking position, i.e., the locking plate 16 is kept in the position shown in FIG. 5, by mistake, the striker B engages the latch 2, thus causing turning of the latter, and the slope 2e behind the first tooth 2c of latch 2 forces the detent 3 to turn in the clockwise direction as indicated in FIGS. 1 and 2 until the latch and the detent come into safety or full engagement. By this turning of the latch 2 (and by the resulted turning of the detent 3), the open plate 8 is caused to turn in the counterclockwide direction as seen in FIG. 5, the third arm 8d of which pushes the hook-shaped part 15a of connecting lever 15, thus causing the latter to turn in the clockwise direction about the pin 14. The pin 20 is thereupon pushed to the left by engagement with the part 150, causing the locking plate 16 to turn in the counterclockwise direction as seen in FIG. 5 about the pin 30 and positions the plate 16 so as to be kept in the position shown in FIG. 4 under the action of turnover spring 24. Thereafter, the door is allowed to be opened by operation of the opening button, followed by clockwise turning (seen in FIG. 4) of open-lever 12 about the pin 13. That is, the unlocking function is attained.

On the other hand, when it is desired to accomplish keyless locking, the inside locking push-knob is operated to position the locking plate 16 and the connecting lever 15 is locking position as shown in FIG. 5 by full lines. Then, after the opening button is operated in the opening direction (i.e., with the parts as positioned in dotted-line positions in FIG. 5), the door is closed. In this case, counterclockwise turning of the open-plate 8 caused by closing of the door cannot change the position of connecting lever 15, since the third arm 8d of open-plate 8 cannot engage with the hook-shaped part 15a of connecting lever 15. Therefore, the lever 15 is left unmoved in the position shown in FIG. 5. Thus, once the door is closed, it is not permitted to open, even if the open-handle is operated, and in this way keyless locking (locking without use of the key) is attained.

The particular advantages given by the present invention are as follows. In door lock devices of the prior art, as shown in FIG. 6, there is provided a latch 32, which has ratchet teeth 32c and 32d engageable with a detent or pawl 33 for stopping the turning of the latch at one side of a pivot point 32a of the same, and a claw 32b engageable with a striker Ba at the opposite side of the pivot point. in other words, the prior device has a force-acting point and a reaction point at opposite sides of a pivot point, while the device of the present invention has a reaction point and a pivot point at opposite sides of a force-acting point.

Therefore, when the same force P acts on the forceacting point (assuming that the distance between the pivot point and the reaction point is equal to that between the force-acting point and the pivot point in the case of the prior device, and that the distance between the force-acting point and the reaction point is equal to that between the force-acting point and the pivot point in the case of the device of the present invention), the pivot point is subjected to a force of 2? and the reaction point to a force of P in the case of the prior art device, while in the case of the device of the present invention, a force of only 1/2? acts on both the pivot point and the reaction point. Accordingly, in the device of the present invention, the latch teeth and the detent are capable of bearing with the same sizes two or four times greater forces than in the prior art design. Moreover, when the force along the longitudinal direction of the car acts upon these parts, there is an undesirable tendency in the case of the prior art design of the latch 32 disengaging from the pawl 33 as indicated in FIG. 7. In the case of the present invention, however, as the parts are arranged as shown in FIG. 3, disengagement of the latch 2 from the detent 3 is restricted by the cover plate 7, so that the correct performance is further ensured in spite of the longitudinal deformation of the car.

Furthermore, the detent 3 is basically a body of revolution, a part of which is cut-out and is shaped to have its arcuate periphery 3a engageable with the the first or second tooth or 2d of the latch 2. Accordingly the detent 3 is formed readily from an ordinary material such as a cold-rolled round bar by rather simple machining at low cost. The surface of this detent is not necessarily machine-finished but, when finished by cutting or grinding, there is attained an excellent smoothness of its engagement with the first or second tooth 2c or 2d of the latch 2. Consequently, a very comfortable tactile feeling is provided in the unlocking operation which is far beyond the reach of prior art devices, in which the parts are formed by pressing'or the like.

Moreover, when the configurations of latch teeth 2c and 2d are defined by convex planes opposing the peripheral arcuate surface 3a of detent 3, concave planes having greater radii of curvature than the surface 30, or by flat planes, it becomes possible to maintain a component of a force to open the door always directed toward the center of the detent 3, irrespective of small errors in manufacturing or assembling. Therefore, occurrence of unintended disengagement between the latch teeth and the detent, due to the abovesaid errors accompanying deformation caused by the torque of the acting force, as is the case of the prior art design, is completely eliminated, whereby the advantageous features of the present invention are assured.

Still further, in the present invention, because the detent is rotatably supported at and along its outer face instead of being a pawl pivoted by a pin as in the case of the prior art, it is possible to make the support surface with a great diameter whereby great strength of the part is assured.

it is to be noted that, in the abovedescribed embodiment there is used as the detent a cylindrical member having a cut-out part. However, as will be appreciated, the same effect is obtainable by using a disk-shaped detent having a cut-out part and pivotably suspended at its outer face.

Generally speaking, in the present invention, when an attempt is made to open or force open the door, a force transmitted from the striker is divided into two components by the latch, and each of these components is received by one or another of two members, respectively. By using a latch of this type together with a detent, which is shaped from a cylindrical or disk like material by cutting out a part thereof and is rotatably supported in a depression of a complementary shape, there is provided a novel door locking device which is of simple design, low cast, and great strength, and imparts a comfortable tactile feeling in operation.

While the invention is herein shown and described as embodied in a preferred form of construction, it is to be understood that various modifications may be made in both the structure and arrangement of the parts of the device without departing from the spirit or scope of the invention. Thus, for example, the engaging part (arcuate wall) 3a of locking detent 3 can be made hookshaped if desired.

We claim:

1. A door locking device for locking a door in a doorway frame of a motor vehicle comprising, a striker fixed to said doorway frame, a base plate fixed to the door, a cover plate fixed to the base plate, a main body of synthetic resin fixedly provided between the base plate and the cover plate, said main body having a recessed portion of a concave cylindrical bearing surface, a latch member rotatably supported on said main body for movement about an axis extending longitudinally of the vehicle, said latch member being adapted to engage with and be rotated into a striker locking position by said striker when the door is closed, a detent rotatably mounted in the recessed portion of said main body for movement about an axis parallel to the axis of the latch member, said detent being rotatably operated by portions of the periphery of said latch member to catch and lock the latch member in said locking position and being operable to release the latch member, an outer periphery of said detent being backed up by said concave cylindrical bearing surface of the main body against forces transverse to the rotational axis of the detent, and a door unlocking mechanism for operating the detent to release the latch member and when a force adapted to disengage the engagement of the striker with the latch member is imparted in the locking position, the force is received by the concave cylindrical bearing surface through the peripheral surface of the detent.

2. The door locking device as claimed in claim 1 in which said striker locked by said latch member in said locking position is in a position substantially intermediate between the rotational axes of the latch member and said detent.

3. A door locking device for locking a door in a doorway frame of a motor vehicle comprising, a striker fixed to said doorway frame, a latch member rotatably supported on said door for movement about an axis extending longitudinally of the vehicle, said latch member being adapted to engage with and be rotated into a striker locking position by said striker when the door is closed, a detent rotatably mounted on the door for movement about an axis parallel to the axis of the latch member, said detent having a configuration which in at least one part thereof constitutes a part of a circular cylinder, said circular cylinder part of the detentbeing rotatably operated by portions of the periphery of said latch member to catch and lock the latch member in said locking position and being operable to release the latch member, a part supported on the door, said door supported part having a concave cylindrical bearing surface for rotatably backing up said detent against forces transverse to the rotational axis thereof, and a door unlocking mechanism for operating the detent to release the latch member and when a force adapted to disengage the engagement of the striker with the latch member is imparted in the locking position, the force is received by the concave cylindrical bearing surface through the peripheral surface of the detent, said detent having a fully circular cylindrical part and said concave cylindrical bearing surface being a fully cylindrical concavity snugly accommodating said fully circular cylindrical part of the detent, and a part circular cylindrical concavity snugly contacting said circular cylindrical part of the detent over a substantial surface thereof without contacting the latch member at any position thereof.

4. The door locking device as claimed in claim 3 in which said latch member is of planar form, the axis of which is the axis of rotation thereof, and being substantially perpendicular to the direction of motion of the latch member relative to the striker, and being substantially parallel to the axis of said detent, and the latch member having a slot extending substantially radially outward to an open end at the periphery of the latch member with said slot being adapted to engage and receive therein the striker.

5. A latch mechanism for a door of a motor vehicle body, including a striker fixed to the vehicle body and a rotary latch member, a recessed body of synthetic resin in which said rotary latch member is mounted, said body having a slot for receiving the striker, said rotary latch member including an integral pivotal mounting portion rotatable in a bore in the body, and a detent rotatably mounted in the recessed body to engage the latch member in the same plane as the slot for receiving the striker.

6. The latch mechanism as claimed in claim 5, in which the pivot point of the latch member is located at the opposite side of the engagement point between the detent and the latch member relative to the striker. 

1. A door locking device for locking a door in a doorway frame of a motor vehicle comprising, a striker fixed to said doorway frame, a base plate fixed to the door, a cover plate fixed to the base plate, a main body of synthetic resin fixedly provided between the base plate and the cover plate, said main body having a recessed portion of a concave cylindrical bearing surface, a latch member rotatably supported on said main body for movement about an axis extending longitudinally of the vehicle, said latch member being adapted to engage with and be rotated into a striker locking position by said striker when the door is closed, a detent rotatably mounted in the recessed portion of said main body for movement about an axis parallel to the axis of the latch member, said detent being rotatably operated by portions of the periphery of said latch member to catch and lock the latch member in said locking position and being operable to release the latch member, an outer periphery of said detent beiNg backed up by said concave cylindrical bearing surface of the main body against forces transverse to the rotational axis of the detent, and a door unlocking mechanism for operating the detent to release the latch member and when a force adapted to disengage the engagement of the striker with the latch member is imparted in the locking position, the force is received by the concave cylindrical bearing surface through the peripheral surface of the detent.
 2. The door locking device as claimed in claim 1 in which said striker locked by said latch member in said locking position is in a position substantially intermediate between the rotational axes of the latch member and said detent.
 3. A door locking device for locking a door in a doorway frame of a motor vehicle comprising, a striker fixed to said doorway frame, a latch member rotatably supported on said door for movement about an axis extending longitudinally of the vehicle, said latch member being adapted to engage with and be rotated into a striker locking position by said striker when the door is closed, a detent rotatably mounted on the door for movement about an axis parallel to the axis of the latch member, said detent having a configuration which in at least one part thereof constitutes a part of a circular cylinder, said circular cylinder part of the detent being rotatably operated by portions of the periphery of said latch member to catch and lock the latch member in said locking position and being operable to release the latch member, a part supported on the door, said door supported part having a concave cylindrical bearing surface for rotatably backing up said detent against forces transverse to the rotational axis thereof, and a door unlocking mechanism for operating the detent to release the latch member and when a force adapted to disengage the engagement of the striker with the latch member is imparted in the locking position, the force is received by the concave cylindrical bearing surface through the peripheral surface of the detent, said detent having a fully circular cylindrical part and said concave cylindrical bearing surface being a fully cylindrical concavity snugly accommodating said fully circular cylindrical part of the detent, and a part circular cylindrical concavity snugly contacting said circular cylindrical part of the detent over a substantial surface thereof without contacting the latch member at any position thereof.
 4. The door locking device as claimed in claim 3 in which said latch member is of planar form, the axis of which is the axis of rotation thereof, and being substantially perpendicular to the direction of motion of the latch member relative to the striker, and being substantially parallel to the axis of said detent, and the latch member having a slot extending substantially radially outward to an open end at the periphery of the latch member with said slot being adapted to engage and receive therein the striker.
 5. A latch mechanism for a door of a motor vehicle body, including a striker fixed to the vehicle body and a rotary latch member, a recessed body of synthetic resin in which said rotary latch member is mounted, said body having a slot for receiving the striker, said rotary latch member including an integral pivotal mounting portion rotatable in a bore in the body, and a detent rotatably mounted in the recessed body to engage the latch member in the same plane as the slot for receiving the striker.
 6. The latch mechanism as claimed in claim 5, in which the pivot point of the latch member is located at the opposite side of the engagement point between the detent and the latch member relative to the striker. 